Department of Chemistry, Saurashtra University, Rajkot-360 005 Manuscript received 9 December 1987, accepted 27 January 1988 Some new 4-thiazolidinones have been prepared bearing 9-aminoacridine moiety by the condensation of Schiff bases from 9-hydrazinoacridine with thiolactic and thio­malic acids. The structures of the product have been characterised by ir spectral study. The products have been screened for antimicrobial activity, and most of which showed moderate activity.